AstraZeneca (AZ) has announced that the first participants have been vaccinated as part of a Phase II/III trial testing a new COVID-19 variant vaccine – AZD2816.

The trial, which is set to recruit approximately 2,250 participants, will administer AZD2816 to individuals who have been previously vaccinated with AZ’s authorised COVID-19 vaccine Vaxzevria or an mRNA vaccine, at least three months after their last dose.

It will also involve non-vaccinated participants – AZD2816 will be administered in a two-dose regimen to these individuals, given four or twelve weeks apart, or given as a second dose following a first dose of Vaxzevria four weeks apart.

“It is important we continue to stay ahead of genetically distinct variants of the coronavirus. AZD2816 should help broaden individuals immune response against emerging variants of concern,” said Mene Pangalos, executive vice president, BioPharmaceuticals R&D, AZ.

“Initiating the Phase II/III trial for AZD2816 means we can be prepared should a variant vaccine be required in the future,” he added.

The AZD2816 vaccine has been designed using AZ’s adenoviral vector platform, with minor genetic alterations to the spike protein based on the beta, or B.1.351/South African, variant.

“Testing booster doses of existing vaccines and new variant vaccines is important to ensure we are best prepared to stay ahead of the coronavirus pandemic, should their use be needed,” said Andrew J Pollard, chief investigator and director of the Oxford Vaccine Group at the University of Oxford.

AZ is expecting initial data from the trial later this year – when available, the trial results will be submitted to regulators for assessment as a ‘next-generation’ booster vaccine through an expedited regulatory pathway, the company said in a statement.